The present invention is generally related to test devices for performing binding assays for determining characteristics of a sample, such as a biological liquid. More particularly, the present invention is directed to assays, which utilize porous carrier materials for transporting reagents.
The device is in the form of test strips commonly utilized in the analysis of various types of samples, particularly, biological fluids, because of their convenience and rapid determination of results. Test strips assays for detecting various clinically significant substances and biological fluids, such as urine and serum, have been very advantageous in assisting the diagnosis and treatment of disease states.
Many binding assay formats are well known in the art and include competition, sandwiched and agglutination assays.
A thorough discussion of prior art assay devices is set forth in U.S. Pat. No. 5,770,458. These assays commonly use test strips comprising an absorbent, porous matrix incorporated with indicator reagents usually of a colorimatrix type. The sample to be tested is contacted with reagent matrix and the indicator response is observed after a certain period of time. Combinations of test strips enable simultaneous test reactions to proceed.
A problem associated with prior art devices, as pointed out in the cited references, is their lack of uniform mobilization of reagents for migration through the strip. The cited reference utilizes a complicated multi-membrane configuration for introducing reagents, which depends upon parallel liquid migration of liquid sample through co-joined membranes.
The present invention provides for a device and procedure for introducing a binding reagent into a strip absorbent membrane in a binding assay device.